Cache element indices for :nth-child and :nth-last-child selectors.

Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 68 matching lines @@
 #include "core/dom/Microtask.h"
 #include "core/dom/MutationObserver.h"
 #include "core/dom/NodeChildRemovalTracker.h"
 #include "core/dom/NodeFilter.h"
 #include "core/dom/NodeIterator.h"
 #include "core/dom/NodeLayoutStyle.h"
 #include "core/dom/NodeRareData.h"
 #include "core/dom/NodeRenderingTraversal.h"
 #include "core/dom/NodeTraversal.h"
 #include "core/dom/NodeWithIndex.h"
+#include "core/dom/NthIndexCache.h"
 #include "core/dom/ProcessingInstruction.h"
 #include "core/dom/RequestAnimationFrameCallback.h"
 #include "core/dom/ScriptRunner.h"
 #include "core/dom/ScriptedAnimationController.h"
 #include "core/dom/SelectorQuery.h"
 #include "core/dom/StaticNodeList.h"
 #include "core/dom/StyleEngine.h"
 #include "core/dom/TouchList.h"
 #include "core/dom/TransformSource.h"
 #include "core/dom/TreeWalker.h"
@@ skipping 1667 matching lines @@
     InspectorInstrumentation::didRecalculateStyle(cookie, m_styleRecalcElementCounter);
 }
 
 void Document::updateStyle(StyleRecalcChange change)
 {
     TRACE_EVENT0("blink", "Document::updateStyle");
 
     HTMLFrameOwnerElement::UpdateSuspendScope suspendWidgetHierarchyUpdates;
     m_lifecycle.advanceTo(DocumentLifecycle::InStyleRecalc);
 
+    NthIndexCache nthIndexCache(*this);
+
     if (styleChangeType() >= SubtreeStyleChange)
         change = Force;
 
     // FIXME: Cannot access the ensureStyleResolver() before calling styleForDocument below because
     // apparently the StyleResolver's constructor has side effects. We should fix it.
     // See printing/setPrinting.html, printing/width-overflow.html though they only fail on
     // mac when accessing the resolver by what appears to be a viewport size difference.
 
     if (change == Force) {
         m_hasNodesWithPlaceholderStyle = false;
@@ skipping 3945 matching lines @@
 #ifndef NDEBUG
 using namespace blink;
 void showLiveDocumentInstances()
 {
     WeakDocumentSet& set = liveDocumentSet();
     fprintf(stderr, "There are %u documents currently alive:\n", set.size());
     for (Document* document : set)
         fprintf(stderr, "- Document %p URL: %s\n", document, document->url().string().utf8().data());
 }
 #endif